A digital camera captures images by allowing the light from the image source to pass through the lens module, forming an image on the image sensor, such as a CMOS or CCD device, and transforming the image data into an electrical signal and storing it. Because the effective area of the image sensor is quite small, the optical axis should be aligned with the center of the image sensor and be perpendicular to the image sensor during the image formation process. For this reason, the appropriate alignment of the lens module with the center of the image sensor is key to ensuring good image quality.
The conventional method of the digital camera assembly is the locating method, for example, fix-hole fit or screw fit, by using components already available in the market. In addition to the position difference, the dimensional difference should also be considered in the total difference approximation. The differences accumulated during the assembly procedure may result in a total difference, which is greater than the tolerance, and therefore degrade the imaging quality of the digital camera.
To solve the problem of total difference control, the present invention provides a method of controlling the total difference effectively. By uniform light source testing before the final fixation of assembly, the total difference could be controlled effectively to ensure the imaging quality of the digital camera.